Radio and TV Antennas — Grounding the Lead-In

The mast gets its own grounding conductor run as straight and short as practical to the grounding electrode system, and the lead-in gets an antenna discharge unit. Straight and short matters because lightning hates to turn corners.

Even in the streaming era there are still dishes and antennas on roofs, and every one of them is a lightning rod unless it is grounded like this section says.

When it applies

This covers receiving antennas and their masts, TV, radio, and similar. A metal antenna up on a roof is a natural lightning target and a path for static, so the mast has to be grounded and the lead-in conductors bonded, with a discharge unit or grounded shield where required. The goal is to give a strike a direct path to earth instead of through the building.

Common mistakes

• Grounding the antenna to a separate rod that is never bonded back to the building's grounding electrode system, that creates a difference of potential.
• Using an undersized or overly long, sharply bent ground conductor instead of a short, straight run.
• Skipping the antenna discharge unit on the lead-in where it is required.

In the field

The mistake I see most is a lonely ground rod at the antenna with no bond to the service ground. Tie them together, a split ground system can push surge current right through the house looking for a path.